John Lukacs is not fond of the presidential “salute”:

Soon after Ronald Reagan assumed his presidency, something new appeared with his image on the television screen. When given a salute by uniformed military personnel, Mr. Reagan would return it, shooting his right hand up to his bare head, his smile suggesting that this was something he liked to do. This unnecessary and unseemly habit was adopted by Mr. Reagan’s successors, including Bill Clinton and especially George W. Bush, who steps off his plane and cocks a jaunty salute.
This gesture is of course quite wrong: such a salute has always required the wearing of a uniform. But there is more to this than a decline in military manners. There is something puerile in the Reagan (and now Bush) salute. It is the joyful gesture of someone who likes playing soldier. It also represents an exaggeration of the president’s military role.